Browsing by Issue Date, starting with "2020-08-31"

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Visible light positioning (VLP) system using low-cost organic photovoltaic cell (OPVC) for low illumination environments
(2020-08-31)
Hong, Chong-You
;
Wu, Yu-Chun
;
Lin, Yu-Hsiang
;
Liu, Yang
;
Chow, Chi-Wai
We propose and demonstrate a received-signal-strength (RSS) based visible light positioning (VLP) system using a low-cost organic photovoltaic cell (OPVC) receiver (Rx). The OPVC is a passive device without the need of external power supply. It could detect VLC signal and harvest energy. Our developed OPVC has a high power conversion efficiency (PCE) of 9.8%. The VLP system can be operated at a low illumination of 130 lux. The regression machine learning (MIL) algorithm is used to enhance the positioning accuracy. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Design of Downlink Synchronization for Millimeter Wave Cellular System Based on Multipath Division Multiple Access
(2020-09-01)
Chiu, Kang-Lun
;
Shen, Pai-Hsiang
;
Lin, Bing-Ru
;
Hsiao, Wei-Han
;
Jou, Shyh-Jye Jerry
This work focuses on the design of downlink receiver for future generation cellular systems. In the multipath division multiple access (MDMA) system, the initial synchronization process includes timing and carrier frequency synchronization as well as home cell search. For the proposed system, the user data is transmitted in time domain and the cell search is based on control signals transmitted in frequency domain simultaneously. Firstly, this paper presents a novel architecture for the joint detection and estimation of both the coarse symbol boundary and the fractional carrier frequency offset based on cyclic prefix in time domain. Secondly, a robust integer carrier frequency offset detection is performed with the primary control tone in frequency domain. Moreover, the position of the secondary control tones is used to obtain the cell ID. Finally, the preamble sequence carried by the secondary control tones is used to detect frame header through differential detection. The simulation results show the proposed synchronization algorithms can achieve detection failure rate less than 1% and the normalized residual carrier frequency offset is less than 5% under the interference of user data. Furthermore, a hardware design targeted at 200 Mbps per-user data rate is realized with memory arbiter to share memory.
周穎政教務長的話
(國立陽明大學牙醫校友會, 2020-09)
周穎政
Analytical Solutions Based on Fourier Cosine Series for the Free Vibrations of Functionally Graded Material Rectangular Mindlin Plates
(2020-09-01)
Huang, Chiung-Shiann
;
Huang, S. H.
;
土木工程學系
;
Department of Civil Engineering
This study aimed to develop series analytical solutions based on the Mindlin plate theory for the free vibrations of functionally graded material (FGM) rectangular plates. The material properties of FGM rectangular plates are assumed to vary along their thickness, and the volume fractions of the plate constituents are defined by a simple power-law function. The series solutions consist of the Fourier cosine series and auxiliary functions of polynomials. The series solutions were established by satisfying governing equations and boundary conditions in the expanded space of the Fourier cosine series. The proposed solutions were validated through comprehensive convergence studies on the first six vibration frequencies of square plates under four combinations of boundary conditions and through comparison of the obtained convergent results with those in the literature. The convergence studies indicated that the solutions obtained for different modes could converge from the upper or lower bounds to the exact values or in an oscillatory manner. The present solutions were further employed to determine the first six vibration frequencies of FGM rectangular plates with various aspect ratios, thickness-to-width ratios, distributions of material properties and combinations of boundary conditions.
Aggregating and disaggregating packets with various sizes of payload in P4 switches at 100 Gbps line rate
(2020-09-01)
Wang, Shie-Yuan
;
Li, Jun-Yi
;
Lin, Yi-Bing
;
資訊工程學系
;
Department of Computer Science
Aggregating multiple small packets into a large packet provides many advantages. For example, multiple small packets can share a single copy of common Ethernet/IP/UDP headers to reduce the percentage of network bandwidth spent on transmitting headers. In the past, packet aggregation and disaggregation were done by a server CPU or a switch CPU, resulting in low throughputs. In this paper, we design and implement packet aggregation and disaggregation functions in the packet processing pipelines of P4 switches. Our novel designs allow packets with various sizes of payload to be aggregated and disaggregated purely in the data plane of a P4 switch. Experimental results show that the achieved throughputs of our aggregation and disaggregation methods can reach 100 Gbps, which is the line rate of the used P4 switch.
Investigation of performance augmentation for natural convective heatsink with the help of chimney
(2020-09-01)
Abbas, Ali
;
Qasrawi, Fatima
;
Wang, Chi-Chuan
;
機械工程學系
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Department of Mechanical Engineering
The effect of adding a plastic chimney on the top of upward horizontal rectangular heatsink under natural convection was investigated experimentally and numerically. The effect of the chimney height, length, depth, inclination, view factor, and conductivity for different fins array dimensions were investigated as well. The presence of low thermal conductivity chimney induces airflow by creating effective pressure difference between the edge and the center of the chimney. Yet higher chimney height results in larger pressure difference. Yet the pressure difference is accentuated with a sharp edge chimney. A smooth edge chimney reduces the pressure gradient and entrained airflow. The chimney with low thermal conductivity is capable to entrain more airflow into the heatsink when comparing with high thermal conductivity chimney (aluminum). The entrained airflow can be as much as 25% higher than the metal chimney. A smaller fin spacing may block the airflow and reversed the heat transfer. For the present configuration, it is found that the chimney is only effective when the heatsink is placed horizontally upward. By employing a transparent chimney, the view factor of the heatsink can be appreciably improved when comparing with opaque chimney.
The relationship between loneliness and working-memory-related frontoparietal network connectivity in people with major depressive disorder
(2020-09-01)
Gao, Mengxia
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Shao, Robin
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Huang, Chih-Mao
;
Liu, Ho-Ling
;
Chen, Yao-Liang
Loneliness affects up to 40 % of middle-aged and older adults, and is closely associated with major depressive disorder (MDD). However, the relationship between loneliness and neural network functioning during executive cognitive processes, such as working memory, in MDD is still unclear. To address this gap, our study recruited 21 medicated MDD patients (mean age = 52.0 +/- 5 years) and 24 matched healthy controls (HC) (mean age = 48.7 +/- 6 years) who completed an n-back fMRI task. For behavioural performance, we observed no significant moderating effect of MDD or loneliness on the task condition effect. However, loneliness was positively associated, and MDD was negatively associated, with the functional connectivity between the inferior parietal cortex and the rostral dorsomedial prefrontal cortex (DMPFC) during task performance. Furthermore, an interactive effect of loneliness and MDD was observed on the functional connectivity between the supplementary motor area and the caudal DMPFC during the n-back task, with loneliness showing a positive relationship in the HC group but a negative relationship in the MDD group with the connectivity. Our results indicated that loneliness may be associated with altered neural regulatory functioning on self-referential processing and action control, which may further depend on the individual's depressive state. These findings can form the theoretical basis for devising intervention programme aimed at improving the mental wellness of the healthy and depressed lonely individuals.
Effect of Thermal Management on the Performance of VCSELs
(2020-09-01)
Pan, Po-Chou
;
Nag, Dhiman
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Khan, Zuhaib
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Chen, Ching-Jung
;
Shi, Jin-Wei
This study investigated the effect of thermal management on the performance of vertical-cavity surface-emitting lasers (VCSELs). It was found that the thickness of silicon substrate, which can serve as the submount for VCSEL packages, has a strong influence on the thermal dissipation of on-chip laser sources, and eventually impacts on their output characteristics. Moreover, the improvements in optical characteristics of the on-chip VCSELs were the best heat dissipation through thinning silicon substrates to 50-mu m thickness combined with electroplated Cu with 100-mu m thickness. In addition, this study also performed COMSOL simulations. The simulation results were consistent with experimental results.
On the Capacity of MIMO Optical Wireless Channels
(2020-09-01)
Li, Longguang
;
Moser, Stefan M.
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Wang, Ligong
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Wigger, Michele
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電信工程研究所
This paper studies the capacity of a general multiple-input multiple-output (MIMO) free-space optical intensity channel under a per-input-antenna peak-power constraint and a total average-power constraint over all input antennas. The focus is on the scenario with more transmit than receive antennas. In this scenario, different input vectors can yield identical distributions at the output, when they result in the same image vector under multiplication by the channel matrix. We first determine the most energy-efficient input vectors that attain each of these image vectors. Based on this, we derive an equivalent capacity expression in terms of the image vector, and establish new lower and upper bounds on the capacity of this channel. The bounds match when the signal-to-noise ratio (SNR) tends to infinity, establishing the high-SNR asymptotic capacity. We also characterize the low-SNR slope of the capacity of this channel.
健保最新資訊─全國各審查分區校友任職幹部名單
(國立陽明大學牙醫校友會, 2020-09)
張宏羽
109年8月16日台北市牙醫師公會會員大會暨第21屆理監事選舉活動花絮
(國立陽明大學牙醫校友會, 2020-09)
黃舜德
Trichostatin A Alleviates Renal Interstitial Fibrosis Through Modulation of the M2 Macrophage Subpopulation
(2020-09-01)
Tseng, Wei-Cheng
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Tsai, Ming-Tsun
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Chen, Nien-Jung
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Tarng, Der-Cherng
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交大名義發表
Mounting evidence indicates that an increase in histone deacetylation contributes to renal fibrosis. Although inhibition of histone deacetylase (HDAC) can reduce the extent of fibrosis, whether HDAC inhibitors exert the antifibrotic effect through modulating the phenotypes of macrophages, the key regulator of renal fibrosis, remains unknown. Moreover, the functional roles of the M2 macrophage subpopulation in fibrotic kidney diseases remain incompletely understood. Herein, we investigated the role of HDAC inhibitors on renal fibrogenesis and macrophage plasticity. We found that HDAC inhibition by trichostatin A (TSA) reduced the accumulation of interstitial macrophages, suppressed the activation of myofibroblasts and attenuated the extent of fibrosis in obstructive nephropathy. Moreover, TSA inhibited M1 macrophages and augmented M2 macrophage infiltration in fibrotic kidney tissue. Interestingly, TSA preferentially upregulated M2c macrophages and suppressed M2a macrophages in the obstructed kidneys, which was correlated with a reduction of interstitial fibrosis. TSA also repressed the expression of proinflammatory and profibrotic molecules in cultured M2a macrophages and inhibited the activation of renal myofibroblasts. In conclusion, our study was the first to show that HDAC inhibition by TSA alleviates renal fibrosis in obstructed kidneys through facilitating an M1 to M2c macrophage transition.
2020.09.19~20陽明牙大會師之平溪孝子山.陽明山五連峰
(國立陽明大學牙醫校友會, 2020-09)
呂名峯
Ga-doped lithium lanthanum zirconium oxide electrolyte for solid-state Li batteries
(2020-09-01)
Mishra, Mrinalini
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Hsu, Che-Wei
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Rath, Purna Chandra
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Patra, Jagabandhu
;
Lai, Hong-Zheng
Cubic-phase Li7La3Zr2O12 (LLZO) garnet is a promising solid electrolyte candidate for next-generation Li batteries. As a viable approach, the desired cubic-phase formation of LLZO relies on elemental doping. In this regard, various dopants such as Al and Ga are doped into the LLZO samples, which are synthesized using a solid-state reaction method. The Al-and Ga-doped LLZO can transform to a cubic-phase garnet at 900 degrees C. After 1200 degrees C sintering, a Li2ZrO3 impurity phase is found for the Al-doped LLZO pellet, which still shows many voids and inhomogeneous particles on the surface. The Ga doping seems to be attractive since it can effectively stabilize the cubic phase and desired microstructure within 900-1200 degrees C. Based on the optimized Ga-doped LLZO (LGLZO), various electrolyte architecture designs are developed that include LGLZO pellet electrolytes with and without poly(ethylene oxide) (PEO)-lithium bis(tri-fluoromethylsulfonyl)imide (LiTFSI)-LGLZO coating, and hybrid electrolyte layers of PEO-LiTFSI, PEO-LGLZO, and PEO-LiTFSI-LGLZO composites. Li//LiFePO4 (LFP) cells with various types of electrolytes are assembled, and their charge-discharge properties are investigated. The all-solid-state Li//PEO-LiTFSI-LGLZO//LFP cell exhibits satisfactory charge storage performance, which has revealed potential for practical applications. (c) 2020 Elsevier Ltd. All rights reserved.
Total-Dose Effect of X-ray Irradiation on Low-TemperaturePolycrystalline Silicon Thin-Film Transistors (vol 41, pg 864, 2020)
(2020-09-01)
Tai, Ya-Hsiang
;
Yeh, Shan
;
Huang, Shih-Hsuan
;
Chang, Ting-Chang
;
電機學院
In The above article [1], the Acknowledgment was deleted in error. Therefore, the Acknowledgment is added below. This change had no influence on the discussion and conclusions in the article.
A Study of the Relationship Between Endurance and Retention Reliability for a HfOx-Based Resistive Switching Memory
(2020-09-01)
Chung, Wei-Min
;
Chang, Yao-Feng
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Hsu, Yu-Lin
;
Chen, Y. -C. Daphne
;
Lin, Chao-Cheng
This study determines the relationship between retention and endurance reliability for a HfOx-based resistive random access memory (ReRAM). A TiN (15 nm) / HfOx (6 nm) / Ti (10 nm) / TiN (40 nm) stacked structure is fabricated and tested to verify its basic characteristics and reliability. The high resistance states (HRS) retention behavior is characterized and is found to degrade over 100x on the endured bits because there is a sequential high temperature procedure. The degradation is reduced slightly to a similar to 30x drop for the endured devices with one single refresh cycle. During the endurance and retention test procedures, the HRS resistance decreases because neutral oxygen vacancy filaments grow and this cannot be reversed. The I-V characteristics for endured devices are also determined. The results show that isothermal treatment causes a gradual SET and RESET process with multiple feasible states. The thermally induced filament degradation model (isolated filament vs. continuous filament) is verified by the relationship between retention and endurance reliability. Design guidance is recommended for an improvement in ReRAM reliability.
A Fully Integrated Step-Down Switched-Capacitor DC-DC Converter With Dual Output Regulation Mechanisms
(2020-09-01)
Chen, Po-Han
;
Cheng, Hao-Chung
;
Chen, Po-Hung
;
電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
This letter proposes a fully integrated step-down switched-capacitor (SC) DC-DC converter using 0.18-mu m CMOS technology for system-on-chip applications. The proposed stepdown switched-capacitor DC-DC converter used two control mechanisms: the switch array modulation technique to regulate the output voltage and the voltage ripple modulation technique to adjust the output voltage ripple of the converter as the loading current varied. As a result, the proposed converter could generate a regulated output voltage with low voltage ripple. The converter core performed at conversion ratios of 1/3 and 1/2 under an input voltage of 1.8 V. The measurement results on 180-nm technology showed that the proposed fully integrated step-down switched-capacitor DC-DC converter could achieve a peak power conversion efficiency of 74.1% and maintain power conversion efficiency at levels over 70% within loading ranges between 1.4 and 5 mA. The output voltage ripple was controlled at levels under 63.4 mV within a loading current ranging between 0.1 and 5 mA.
Accumulated plasmonic effects of gold nanoparticle-decorated PEGylated graphene oxides in organic light-emitting diodes
(2020-09-01)
Chuang, Ming-Kai
;
Lin, Chun-Hao
;
Chen, Fang-Chung
;
交大名義發表
;
光電工程學系
Amphiphilic Au nanoparticle-decorated PEGylated graphene oxides (Au@PEG-GO) are used to construct multiple plasmonic nanostructures for enhancing the performance of organic light-emitting diodes (OLEDs). Because of the long side-chains of the Au@PEG-GO nanocomposites, the nanoparticles can be well dispersed both in organic and aqueous solvents, allowing them to be incorporated readily into the buffer layers, such as poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT:PSS) and the organic photoactive layers within OLEDs during the soultion processes. Herein, the Au@PEG-GO nanocomposites are blended into either the PEDOT:PSS or the emissive layer of OLEDs to trigger surface plasmonic effects, thereby improving the device efficiencies. The current efficiencies are improved by ca. 20% for both cases. More importantly, the simultaneous addition of the Au@PEG-GO nanocomposites into both layers leads to even pronounced plasmonic effects. Under the optimized condition, the current efficiency is enhanced by up to 38%, suggesting the plasmonic fields from both layers attributed to the device enhancement. We anticipate that the accumulated plasmonic effects originating from the multiple plasmonic nanostructures will open up new avenues for improving the performance of various solution-processed optoelectronic devices involving organic dyes.
財團法人宜學教育基金會創立緣起
(國立陽明大學牙醫校友會, 2020-09)
簡銘杉
Simultaneous Heterogeneous Sensor Localization, Joint Tracking, and Upper Extremity Modeling for Stroke Rehabilitation
(2020-09-01)
Chen, Jiun-Fu
;
Wang, Chieh-Chih
;
Wu, Eric Hsiao-Kuang
;
Chou, Cheng-Fu
;
電機工程學系
In stroke rehabilitation systems and applications, reliability, accuracy, and occlusion should be taken into consideration. Unfortunately, most existing approaches focus primarily on the first two issues. However, during the stroke rehabilitation process, occlusion leads to incorrect judgements even for medical staff. In order to tackle these three important issues simultaneously, we propose a heterogeneous sensor fusion framework composed of an RGB-D camera and a wearable device to consider occlusion and provide robust joint locations for rehabilitation. To fuse multiple sensor measurements when compensating for occlusion, we apply heterogeneous sensor simultaneous localization, tracking, and modeling to estimate the locations of joints and sensors and construct an upper extremity model for occlusion situation. Virtual measurements based on this model are used to estimate the joint's location during occlusion, and a virtual relative orientation technique is applied to relax system limitations regarding orientation. Experimental results using the proposed approach with synthetic data and data collected from ten subjects show a 4.6 cm error on average and about 15 cm error on average during occlusion. This constitutes a more robust approach for stroke patients which takes into account these three important issues.